1. Field of the invention
This invention relates in general to electrically driven centrifugal submersible well pumps, and in particular to a gas separator for separating gas from the well fluid prior to reaching the pump.
2. Description of the Prior Art
Submersible well pumps of the type concerned herein are centrifugal and driven by a downhole electrical motor. A pump will have a large number of stages, each stage having an impeller rotatably driven within a diffuser. These pumps are used to pump large volumes of fluid, such as oil and water from wells.
Most oil wells typically will also produce some gas. If the gas is of sufficient volume, it can reduce the performance of the pump. In these circumstances, gas separators are mounted in the assembly below the pump and above the motor and the mechanical seal.
Prior art gas separators utilize a rotatably driven rotor within a cylindrical housing. The rotor has at least one blade or vane. The vane will impart a centrifugal force to the well fluid flowing through the housing. This centrifugal force tends to separate the liquid components from the gas components because of differance in densities, with the liquid components locating near the outer wall of the housing, and the gas remaining near the shaft.
A discharge member mounts above the rotor. The discharge member will provide a passage from the central portion of the rotor to the exterior of the gas separator to discharge gas. The discharge member also provides a liquid passageway for the remaining portion of the well fluid to flow upward toward the intake of a pump.
While workable, improvements to the rotor and discharge member are desirable, both in the efficiency and the cost of the members.